Iris Vs Shutter Speed

Author: John Honovich, Published on Jan 24, 2013

Surveillance cameras must deal with wide variations of lighting -- automatically and continuously. It can be 10,000+ lux during the day and under 1 lux at night. In a few seconds, lighting can drop dramatically, for example, if the sun goes behind a cloud or if a person turns off the lights. As lighting changes, the camera needs to adjust on its own without having a photographer optimize the scene.

Surveillance cameras do this through two means - controlling the size of the iris or the speed of the shutter. Indeed, often cameras can control both simultaneously. In this tutorial, we compare the two and explain how they relate.

*** **********, *** ******* ****************** *************.

Controlling ***** *****

******* *** **** "**********" - **** ****** **** **** *** little ** *** **** *****, ** ***** ** ** **** right.

exposure contrast

** ******, *** ****** ** ***** **** ** '**** *****' for * ****** ******* ** *** **** ***** ** ** the *****. ** *** ******* *****, ** *** ****** **** open, *** ***** ***** **** *** **** ***** *** *** camera ***** **** ** ****** ** **** .

Two "********"

***** ** ******* *** ***** **** ***** ** * ****. If *** **** ** ******* *** ***** *** *** ** it *** ****:

  • **** *** **** ****** (** *******); *** *******, **** ** adjusting ******* ****
  • **** *** **** ****** (** *******); *** *******, **** ** adjusting ********** *****

Why *** **. *** *****

**** ******* (***** ** ****** **** ****) **** ****** ** adjusting *** ******* *****. *****'* ** ****** ****.

***** ******* (**** ** * **** ****) *** **** *** iris **** *********** ****** ** *******. ** ********, *********, **** will **** ** **** ** ******* *** ******* ***** ** well.

*** **** ********** ** **** *** ******* ****** *** ****** limitless ***** **** *** * **** ******** **********. *** *** only **** *** **** ** **** ***** *** **** ********** cannot ******* ******** ****. *******, *** ******* *** ** **** to **** **** *** ** **** ** *** ****** ************ (and ****) *******. ***** **** **** ***** *** **** ***** and * *** ******** ******* ** **** **********, ** *** also****** ******* ************ ***** ****** ******* *******.

** *** ***** ****, *********** *** **** *** ***** *** a ****** ***** ** ****. *******, **** *** ******* ********* benefit ** ************ *** **** *** **** ** **** ********** because *** ****** * ***** ******** ** ** **** **** make *** ***** **** *** *******. *** ******** ** ***** ********.

Practical ******

*** ****-*****. ******** ****:

  • ******* **** ** ************* *** ************ ******** *** ****** ** light **** ******
  • **** *** ** **** ** ********* *** ***** ** *** opening *** ***** (****) ** *** ****** ** **** ***** enters (*******)
  • ******* ******** ***** *********** *** ********** *** ******* ** **** of ***** *** **** *** **** ** ********
  • **** ******** *** ********* *** ****** *** *** ** ** neither ********* *** ********* *** **** ************ ************
Login to read this IPVM report.
Why do I need to log in?
IPVM conducts unique testing and research funded by member's payments enabling us to offer the most independent, accurate and in-depth information.

Related Reports

Batteries For Alarm Systems Tutorial on Jul 11, 2017
Alarm systems use backup batteries in order to continue working if an intruder attempts to disable the alarm by cutting power to the building. In...
H.265 / HEVC Codec Tutorial 2017 on Jun 30, 2017
For years, video surveillance professionals have talked about the potential for H.265. Now, in 2017, H.265 is starting to gain mainstream...
Selling and Valuing Security Integrators on May 12, 2017
This ia a tutorial in how to (1) determine your security integrator's value and (2) to sell your security integrator. If you own an integrator,...
Technician Personal Protective Equipment (PPE) Guide on May 12, 2017
Technicians encounter multiple hazards when running wires and installing security devices. Wearing personal protective equipment, or PPE, helps...
Varifocal Vs Fixed Lens Statistics 2017 on May 04, 2017
Varifocal camera lenses provide more flexibility at installation time, but come at a higher cost. Fixed lens cameras reduce hardware costs, but can...
Duress Codes For Alarms Systems on May 02, 2017
An alarm system can call for help in the event of an attempted break in, but only if it is armed. If an adversary forces an authorized user to...
Burglar Alarm Strobes Guide on Mar 31, 2017
Strobes provide visual notification of alarm incidents, as sirens are used to give audible notification. Using a strobe gives alarm users and alarm...
Burglar Alarm Sirens Guide on Mar 27, 2017
Sirens are used to alert users to an alarm condition. In this note, we examine how to choose, locate, and install alarm sirens, including Siren...
Glass Break Sensor Tutorial on Mar 21, 2017
Burglars often break glass windows to get into a house. Using glass break detectors in conjunction with alarm contacts is a good way to protect the...
Alarm Panic Switches Tutorial on Mar 16, 2017
Panic switches allow silently triggering an alarm system when it is otherwise disarmed. In this tutorial we explain and contrast the 7 most common...

Most Recent Industry Reports

Anixter - Falling Video Prices on Jul 26, 2017
Falling video prices are such a concern that it has become a notable topic for Anixter's financial results and Anixter's executives. In this...
Bosch G-Series Intrusion Tested on Jul 26, 2017
Bosch is one of the biggest names in intrusion, and the company's G-Series panels are their most advanced commercial and high-security panels. But...
Healthy Skepticism for Deep Learning Is Prudent on Jul 26, 2017
The hype for deep learning in video surveillance is accelerating. Between the race to the bottom and dearth of a 'next big thing', certainly pent...
$28M Drone Detection Startup Examined (Dedrone) on Jul 25, 2017
Dedrone has received ~$28M in funding to build what they call an "automatic anti-drone solution", a system to detect drones, and then automatically...
Dahua Suffers Second Major Vulnerability, Silent [Finally Acknowledges] on Jul 25, 2017
Less than 3 months ago, Dahua received DHS ICS-CERT's worst score of 10.0 for their backdoor. Now, Dahua has received another 10.0 score for a new...
Hikvision H.265+ Bullet Tested (2035) on Jul 24, 2017
Continuing our tests of Hikvision's new low cost Value Plus line, we bought and tested the 3MP DS-2CD2035FWD-I, now including H.265+. We shot the...
Sports Stadium Security Design Recommendations on Jul 24, 2017
Sports stadiums pose many challenges for designing security systems. The facilities vary from being mostly vacant, to packed with tens of thousands...
Competing Against Convergint on Jul 24, 2017
No integrator is more aggressively expanding than Convergint Technologies. Owned and funded by private equity firm KRG, Convergint has acquired...
Security Robots Are Just Entertainment on Jul 21, 2017
Great entertainment, no real security value.  That is the happy (or sad) state of security robots in 2017. Knightscope robot's drowning, the...
Wireless Burglar Alarm Sensors Guide on Jul 21, 2017
Wireless sensors for burglar alarm sensors are an increasingly common option for the historical labor intensive wired alarm systems. However,...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact